Lyme disease remains a significant public health problem in the United States and prevention involves exposure reduction and the use of newly developed vaccines. The goal of this study is to develop methods to better anticipate where and when infected ticks are likely to be most abundant. Using seven years worth of field data gathered in southeastern New York, the authors have reported that periodic heavy production of acorn crops (masting) establishes conditions for high rates of Borrelia bugdorferi transmission among the reservoir-vector populations. The proposed research is intended to test whether: the density of infected nymphal ticks is related to earlier acorn production; that density-dependent dispersal of white-footed mice links Bb in adjoining, different habitats; that greater densities of reservoir incompetent species in maple woodlands, as opposed to oak forests result in lower levels of infections in ticks; and, that abiotic conditions in maple forests may increase the survival of immature ticks. Finally, perturbation studies of two populations of potential reservoirs will be performed to examine the effects of faunal diversity on infection prevalence.